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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Fri, 30 Apr 2021 17:02:23 -0700
Message-ID: <CAKwvOdkN3cDof=aEwRRuSEghTZt57TuZucP=pGvpmUXiPSYTWQ@mail.gmail.com>
Subject: Re: [PATCH] KEYS: trusted: Fix memory leak on object td
To:     Colin King <colin.king@canonical.com>
Cc:     James Bottomley <jejb@linux.ibm.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Mimi Zohar <zohar@linux.ibm.com>,
        David Howells <dhowells@redhat.com>,
        James Morris <jmorris@namei.org>,
        "Serge E . Hallyn" <serge@hallyn.com>,
        Nathan Chancellor <nathan@kernel.org>,
        linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        kernel-janitors@vger.kernel.org,
        clang-built-linux <clang-built-linux@googlegroups.com>
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On Fri, Apr 30, 2021 at 4:37 AM Colin King <colin.king@canonical.com> wrote:
>
> From: Colin Ian King <colin.king@canonical.com>
>
> Two error return paths are neglecting to free allocated object td,
> causing a memory leak. Fix this by returning via the error return
> path that securely kfree's td.
>
> Fixes clang scan-build warning:
> security/keys/trusted-keys/trusted_tpm1.c:496:10: warning: Potential
> memory leak [unix.Malloc]
>
> Fixes: 5df16caada3f ("KEYS: trusted: Fix incorrect handling of tpm_get_random()")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  security/keys/trusted-keys/trusted_tpm1.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
> index 469394550801..aa108bea6739 100644
> --- a/security/keys/trusted-keys/trusted_tpm1.c
> +++ b/security/keys/trusted-keys/trusted_tpm1.c
> @@ -493,10 +493,12 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
>
>         ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE);
>         if (ret < 0)
> -               return ret;
> +               goto out;
>
> -       if (ret != TPM_NONCE_SIZE)
> -               return -EIO;
> +       if (ret != TPM_NONCE_SIZE) {
> +               ret = -EIO;
> +               goto out;
> +       }
>
>         ordinal = htonl(TPM_ORD_SEAL);
>         datsize = htonl(datalen);
> --
> 2.30.2
>


-- 
Thanks,
~Nick Desaulniers